How to write the notice of the start of the training class?

As the person in charge of the training course, sending the notice of commencement to the students who have signed up for the training course must include the following important information:

First of all, the date, place, time and arrangement of the training course.

Second, if conditions permit, you can also introduce the teachers who teach.

Third, students can't come to the training because of something, so they should contact the responsible teacher for leave.

The above is my opinion, for reference only. I hope my answer can help you and make you satisfied.